Establishment of the maternal-fetal interface is critically important since is at this level that uteroplacental and fetoplacental blood flows are regulated, and dysfunction is associated with diseases of pregnancy, e.g. preeclampsia. We observed a central role for Gap junctions and specifically Gx4S assembly in enabling pregnancy adaptation of endothelial vasodilatory capacity. We now provide evidence that it may be altered quite negatively by the numerous chemokine's reported to be secreted by the trophoblast. cAMP/cGMP as well as shear stress is also implicated by our studies to promote Gap junction formation for endothelial cell-cell communication. Under chronic hypoxic conditions (preeclampsia), increases in growth factors and inflammatory cytokines e.g. VEGF and TNF are reported to cause severe detrimental alterations in the functional angiogenic and NO synthetic responses to VEGF and FGF2 via alterations in specific G-protein coupling transducers (GNA14 and GNA14). The central theme of this POl is that cell-cell communication between endothelial cells underlies normal functions and that the high levels of growth factors and cytokines (VEGF & TNF) released in preeclampsia will disrupt Gap junction assembly/function thus compromising vasodilator and angiogenic function. We also explore therapeutic strategies to reverse Gap junction dysfunction. Project I ERK and Src as negative regulators of pregnancy adapted uterine artery endothelial function. Project II Shear stress and Gap junction-mediated pregnancy adaptations of uterine artery and human umbilical vessel endothelial cell function. Project III the roles of GNA14 and GNA11 in human fetal endothelial cell function. Continuing strong synergy of these projects is facilitated through leadership in the Administrative core (Gore A) and efficient utilization of the Live Cell Imaging and Protein Analytical Gore B and Cell and Immunocytochemistry Gore G. Interactions between with Projects will also provide novel insights into cell-cell communication between endothelial cells, so providing a much deeper understanding of the inter/intracellular mechanisms in normal and abnormal pregnancies (e.g. preeclampsia). RELEVANCE: The studies represent major advancements in understanding the effects of uterine and placental endothelial adaptation via Gap junction-mediated cell-cell communication at the maternal fetal interface. This leads to indepth understanding of the inter/intracellular mechanisms at the maternal-fetal interface in normal and abnormal pregnancies (e.g. preeclampsia with lUGR).